Paper tubes



Dec. so, 1958 H. BUNZL ETAL 2,866,465

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PAPER TUBES 4 Sheets-Sheet 4 Filed March 22, 1954 N a u q n I'll-Ill VII I I I l I I I I I I l l N /N VE N TORS H0 00 804/1. gPom 5015mm ATTORNEYS Unite PAPER TUBES Hugo Bunzl and Paul Schechner, London, England, assignors to Cigarette Components Limited, London England Application March 22, 1954, Serial No. 417,906

Claims priority, application Great Britain March 24, 1953 2 Claims. (Cl. 131-208) The present invention relates to a continuous tube formed of paper and having a succession of longitudinally spaced cylindrical plug lengths enclosed within it, and to an individual plug element formed by subdividing the tube. I

The cylindrical plug lengths may be filter plugs, formed for example of rolled lengths of crepe paper, cotton wool or other vegetable fibre material, mineral fibre material, animal fibres, artificial silk and synthetic fibres, plastic foam materials and the like, and a tube according to the invention and containing such filter plugs is well adapted, after division into suitable lengths, to serve as cigarette tubes or mouthpieces for cigarette tubes the plug lengths constituting fitted smoke filters.

A continuous paper tube in accordance with the invention comprises a plurality of plug lengths spaced from one another axially of the tube, an inner tube formed from a strip of relatively stout paper fitting aroundthe plug lengths and having a longitudinal butt joint, and an outer tube formed from a strip of relatively thin paper surrounding the butt jointed inner tube and having a longitudinal lapped and stuck seam.

An embodiment of the invention will now be described by way of example, with reference to the accompanying diagrammatic drawings, wherein:

Figure 1 is a view in elevation of a machine for making the article of the invention,

Figure 2 is a plan view of the machine shown in Figure 1,

Figure 3 is a section taken on the line 3--3 in Figure 2 and showing a detail drawn to a larger scale,

Figure 4 is a section taken on the line 4-4 in Figure 3 and showing a detail drawn to a larger scale than that used in Figure 3,

Figure 5 is a longitudinal section to an enlarged scale through part of the continuous plug rod produced by the machine,

Figure 6 is a section taken on the line 6-6 in Figure 5 and drawn to a larger scale,

Figure 7 is a schematic circuit diagram,

Figures 8A, 8B and 8C show the waveforms of electric signals produced in the circuit of Figure 7, and

Figure 9 is a view of a detail of the machine in Figures 1 to 4.

A strip 10 of relatively stout paper, e. g. parchment paper, is passed from a storage roll 11, through a tensioning device 12, against the gluing wheel of a gluing device 13 and into a garniture 14. Simultaneously a strip 15 of thinner paper, e. g. cigarette paper, is unreeled from a storage roll 16 and is laid on to the underface of the strip 10 as it enters the garniture 14. The strip 15 may engage a gluing device 17 (Figure l) which applies glue to the face of the strip 15 that engages the underface of the strip 10, the glue securing the two strips firmly together.

The filter material has the form of short lengths of, for example, crepe paper rolled into cylindrical shape.

2,866,465 Patented Dec. 30, 1958 Each length is enclosed in a wrapper 18 (Figures 5 and 6) having a longitudinal lapped joint, so that the exterior of the length is smooth. The lengths are fed from a hopper 19 to a vibrating conveyor chute 20, and thence on to a rotating disc 21, the upper surface of which is smooth and provided with a peripheral groove 22. The lengths are thrown by centrifugal force radially outwards against a stationary wall 23 and engage in the groove 22. The lengths lying end to end in the groove feed themselves into the mouth of a tubular guide 24. A rotating roller 25 protruding through the wall 23 engages the upper ends of lengths that are standing on end in the groove and throws them towards the centre of the disc, while a rotating roller 26, also protruding through the wall 23, does the same for anylength that is lying on top of another length in the groove 22. Means for driving the disc 21 and the rollers 25 and 26 are not shown.

The rate of delivery of the lengths to the tubular guide 24 is sufiicient for the guide to be kept full; from the guide they pass into approximately-radially disposed bores 27 in the periphery of a rotating indexing wheel 28. The lengths are fed in turn from the indexing wheel into respective spaces between the teeth 29 of a rotating wheel 30, each length being blown from its respective bore 27 by a puff of compressed air applied through a respective bore 31 in the wheel 28. A guide (not shown) may be provided between the two wheels to direct the lengths blown from the wheel 28 into their respective spaces on the wheel 30. As indicated in Figure 3 the periphery of the wheel 30 is not a smooth cylinder, but is provided with a number of flats, some of which receive the teeth 29 and the others of which comprise the spaces receiving the lengths of filter material. The length of each tooth 29, measured circumferentially of the wheel 30, is equal to the length of the space to be produced in the finished plug rod between two successive lengths; the length of the spaces, also measured circumferentially of the Wheel, is sufficient for the lengths to be an easy fit therein. The flats receiving the lengths are grooved, as shown in Figure 4, the lengths entering the grooves and being retained therein by suction applied through respective bores 32. The teeth 29 are fixed to the wheel 30 by removable pins 33, and can thus be removed and exchanged for teeth of longer or shorter circumferential length.

The lower run of the periphery of the wheel 30 engages the strip 10, and as each length of filter material onthe wheel is travelling parallel with the strip, the suction in the respective bore 32 is released, so that the length is deposited on the strip and is fed with the strips 10 and 15 into the garniture 14. With the arrangement described a plurality of lengths thrown at random into the hopper- 30 is fed in succession at equally spaced intervals on to the upper face of the strip 10 with their longitudinal axes parallel to the length of the strip 10. The lengths are held on the strip 10 by the adhesive 10a applied to its upper side by the device 13.

The part of the strip 10 receiving the lengths is bent to a U-shape just before it enters the garniture 14 by a prefolder 34. In the garniture the strip 10 is bent around the lengths until its two edges meet and form a butt joint 10a (Figure 6). The cigarette paper strip is wrapped around the strip 10, leaving one border 15a (Figure 6) projecting more or less radially upwards, which thereafter engages a moistening wheel 35a and a cooperating press wheel 3511, the portion 15a subsequently being pressed down by the garniture to form a longitudinal lapped and stuck seam. The adhesive 10a in the resulting continuous filter plug rod is dried by passing the rod through an electric heater 36 maintained at the required tem erature. The two strips and the lengths of filter material are pulled through the garniture in known manner by a flexible tape 37 (Figure 1) which Wraps around the outside of the strip 15.

The continuous plug rod leaving the heater 36 is cut into sections by a rotatably mounted knife 38, the cut sections passing via a chute or conveyor 39 to a packing station or to a cigarette-making machine.

In Figure 5, which shows a longitudinal section of part of a continuous plug rod, the broken lines z-z indicate the lines along which the continuous plug rod will be cut to form individual plug elements. In some cases however the cut sections that are fed to the packing station each comprise a number (usually an even number) of plug elements.

The strips and are under tension in the machine and there is therefore a tendency for them to stretch. The percentage of stretch per unit length is determined by many factors, for example, the quality of the paper and the humidity of the surrounding atmosphere, and it may vary during the use of a single storage reel 11 or 16. The result of a change in the percentage of stretch is that the knife does not cut accurately through the centre of a length of filter material or a space, and in practice a close watch has been kept by a skilled operator and appropriate adjustments made. A control system which obviates the need for constant control by an observer will now be described.

The speed of travel of the strips 10 and 15 is determined by the speed of travel of the tape 37 and thus by the speed of rotation of a driving pulley 40 (Figure 1) for the tape. The pulley 40, the knife 38 and a continuously variable-speed gear 41 are driven together from a shaft 42 connected to a driving motor which is not shown, the power take-off for the pulley 40 being through a gear 43. The knife 38 is connected to the shaft 42 by chainwheels 44 and 45 and a chain 46 giving a 1:1 ratio, and the input shaft of the continuously variable speed gear 41 is connected to the shaft by a gear 47. The ratio provided by the variable gear 41 is varied by movement of a control handle 48 thereof in the directions of the arrows at in Figure 2, such movement of the handle being produced by a servo mechanism 49, which is mounted on the gear 41 and has a moving member 50 embracing the handle 48. The output shaft 51 of the variable gear 41 is connected to drive the wheel 30 by chain wheels 52 and 53 and a chain 54. The wheel 30 is connected to drive the Wheel 28 bytwo chain wheels 55 and 56 and a chain 57.

Thus, by operation of the handle 48 of the variable gear 41, the rate at which the lengths of filter material are laid on the strip 16 can be varied to adjust the lengths of the spaces between successive lengths.

As the continuous plug rod emerges from the heater 36 it is scanned by a thin slit of light produced by a source 58 (Figure 1) of conventional form. The light transmitted by the rod is received by a photocell 59, the amount of light transmitted by the rod varying in dependence upon whether a length of filter material or a space is present in the part of the rod being scanned by the said slit of light. The waveform of the signals produced by the scanning is shown in Figure 8A. A disc 60 fixed to the shaft 42 has the form shown in detail in Figure 9A. A source 61 and a photocell 62 are disposed to scan a narrow slot 63 in the disc with a thin slit of light, each scanning of the slot 63 producing a pulse, such as the pulses y shown in solid lines in Figure 8B.

The signals from the photocells 59 and 62 are fed through respective amplifiers 64 and 65 to an adding circuit 66, in which the two signals are added together to give the resulting waveform shown in solid lines in Figure 8C. The output from the adding circuit 66 is fed to a relay 67 including two switches 68 and 69 which are operated alternatively to supply control voltages to the servo mechanism 49. The circuit is supplied with power from a source 70 via a time-sharing circuit 71 whose function will be described hereinafter.

The leading edges of the pulses derived from the scanning of the continuous rod are arranged to slope somewhat, as shown in Figure 8A. The apparatus is adjusted until, with the knife 38 cutting accurately along the lines zz, the pulses produced by the scanning of the disc 60 (e. g. the pulses y in Figure 8B) coincide with the centres of the leading edges of the pulses shown in Figure 8A, with the result that a voltage of maximum amplitude Y (Figure 8C) is fed from the adding circuit 66 to the relay 67. The relay is not responsive to a voltage of amplitude Y and accordingly no change is made by the servo mechanism 49 to the rate of deposition of the lengths of filter material.

If the rate of deposition of the lengths is too low the pulses from the photocell 62 will occur in front of the leading edges of the pulses from the photocell 59, i. e. the pulses from the photocell 62 may be regarded as occupying positions such as z (Figure 8B in broken lines), with the result that the maximum amplitude of the voltage fed by the adding circuit 66 to the relay 67 falls to a value Z (Figure 8C) lower than the value Y. The relay 67 is responsive to the voltage Z to close (say) the switch 68, and thereby feed a signal to the servo mechanism 49 that causes the mechanism to increase the rate delivery of the lengths. When the rate of delivery again reaches the correct value the voltage fed to the relay 67 increases to the value Y and the switch 68 opens, so that the servo mechanism stops increasing the said rate of delivery and maintains it at its new value.

Similarly, if the rate of deposition is too high, the pulses from the photocell 62 occur behind the leading edges of the pulses from the photocell 59, and may be regarded as occupying positions such as x shown in chain dotted lines in Figure 8B. As a result the maximum amplitude of the voltage fed to the relay 67 increases to a value X (Figure 8C) higher than the value Y, the relay responds to the increased voltage to close the switch 69, and a signal is thereby fed to the servo mechanism 49 that causes it to decrease the rate of delivery of the lengths until the voltage fed to the relay decreases again to the value Y.

The time-sharing circuit 71 may be employed if the circuit proves to be too sensitive in use and hunts. The circuit 71 is arranged to permit and prevent operation of the servo mechanism 49 in some predetermined sequence. For example, the circuit may be so arranged that during each seven seconds the servo mechanism is permitted to operate for an interval of 3 seconds, and then is prevented from operation during the remaining interval of four seconds. The circuit 71 may comprise, for example, a thermally-operated relay or a cam-operated switch, the cam being driven by a synchronous motor or by some continuously rotating member of the machine.

We claim:

1. A rnulti-plug unit adapted to be cut into individual mouthpiece sections to be delivered to a cigarette making machine, said units comprising a paper tube enclosing a plurality of plug lengths spaced from one another axially of the tube, the paper tube being constituted by an inner tube formed from a strip of relatively stout paper fitting around the plurality of plug lengths and having a longitudinal butt joint, and an outer tube of the same length as the inner tube, the outer tube being formed from a strip of relatively thin paper surrounding the butt jointed inner tube and having a longitudinal lapped and stuck seam.

2. A multi-plug unit adapted to be cut into individual mouthpiece sections to be delivered to a cigarette making machine, said units comprising a paper tube enclosing a plurality of plug lengths spaced from one another axially of the tube, a like plurality of innermost tubes each formed from a strip of relatively thin paper and fitting around a respective plug length, each innermost tube being of the same length as its respective plug length and having a longitudinal lapped and stuck seam, the paper tube being constituted by an inner tube formed from a strip of relatively stout paper fitting around the plurality of plug lengths and having a longitudinal butt joint, and an outer tube of the-same length as the inner tube, the outer tube being formed from a strip of relative- 1y thin paper surrounding the butt jointed inner tube and having a longitudinal lapped and stuck seam.

References Cited in the file of this patent UNITED STATES PATENTS Re. 20,138 Molins Oct. 20, 1936 6 Hamisch Dec. 23, 1902 Davidson May 5, 1936 May Mar. 14, 1939 Podmore Oct. 29, 1940 Davidson Nov. 12, 1940 Stores Oct. 7, 1941 Lobley et a1. July 15', 1947 Wellborn Apr. 4, 1950 Murdock et al. May 26, 1953 Troy Feb. 23, 1954 FOREIGN PATENTS Switzerland July 1, 1952 Great Britain Mar. 15, 1928 Great Britain May 24, 1945 France Feb. 14, 1927 

